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Scanning Electron Microscope

Scanning Electron Microscope. Innovation Center, Analysis performed 16/9/10 Supervisor: Birgir Jóhannsson Students:, Frímann, Hafdís, Helgi, Ísak, Þorvaldur. Electron microscope in general. Light microscopes can get 2000x magnification

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Scanning Electron Microscope

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  1. Scanning Electron Microscope Innovation Center, Analysis performed 16/9/10 Supervisor: Birgir Jóhannsson Students:, Frímann, Hafdís, Helgi, Ísak, Þorvaldur

  2. Electron microscope in general • Light microscopes can get 2000x magnification • Electron microscopes (EM) can get up to 2.000.000x magnification • The resolution is determined by focusing of the electron beam • Two most common types, Transmission EM and Scanning EM • SEM at the Innovation Center

  3. The electron beam • The electrons are generated from a small ceramic tip, radius of the tip about 0.5μm • The acceleration voltage was 20 kV • The electrons are focused to a spot 0.5-5nm in diameter

  4. Elemental analysis • Energy-dispersive X-ray spectroscopy • Electron from an inner shell is excited and ejected from the atom • Outer shell electron falls to the gap left by the ejected electron and emits an X-ray • Wavelength of the X-ray is characteristic for the atom

  5. Conclusions • Electron microscopes and get an enormous magnification and determine chemical compositions of surfaces with X-ray analysis. • EM can also scan over an area and between points. • The area around Fjarðarál is polluted. • Coins from the early 1980’s differ in composition as opposed to present day.

  6. References • http://en.wikipedia.org/wiki/Scanning_electron_microscope • http://www.purdue.edu/rem/rs/sem.htm

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